1. Field of the Invention
The present invention relates generally to neutron detection using a Helium-3 (3HE) neutron detector, and specifically relates to a 3HE neutron detector including a guard structure.
2. Discussion of the Prior Art
Helium-3 (3HE) neutron detectors are used to detect free neutrons. In general, 3HE neutron detectors include an anode extending through a cathode shell, with an insulator separating the anode from the cathode shell. To detect neutrons, a quantity of 3He gas is provided within an interior of the cathode shell. Ions/particles resulting from neutron reactions within the cathode shell will collide with the 3He gas to produce free electrons. These free electrons are drawn to the anode, whereupon the free electrons generate a signal/electronic pulse. This signal/electronic pulse is analyzed to determine a neutron count rate. Turning now to FIG. 4, an example of a previously known neutron detector 300 is shown. The neutron detector 300 includes an exterior shell 320, a central structure 340, and an insulating portion 360. However, in operation, leakage current forms on the surface of the insulator as a result of degradation or breakdown of the insulator. Within the example of FIG. 4, leakage current can travel along the insulating portion 360 in a first direction 380 (shown generically/schematically as an arrow in FIG. 4). The leakage current traveling along the first direction 380 can reach a structure end 342 of the central structure 340. This leakage current can adversely affect a measuring capability of the neutron detector 300 by generating a false current. Specifically, this leakage current can produce false detection of neutrons and can affect the neutron count rate. Accordingly, there is a need and it would be beneficial to attend to the issue concerning leakage current flowing to the anode.